I can sort of see the point, but: carry a whole spare wheel, instead of a much lighter and foldable tube, or even just a tiny box containing patches and glue? I'm no weight weenie, but carry a whole spare wheel? If I'm riding 50-60 miles I don't want the load, and if I'm only hopping across town a mile or so, I'd rather walk the bike home than have to carry a spare wheel.
I think a problem might be this: anyone who feels unequal to the task of just changing a tube, or fixing a puncture, is probably going to feel changing a wheel is beyond them as well.
Also of course, you don't need to add disc brakes to the equation. All rim brake designs stay attached to the bike already.